Bath lift apparatus

ABSTRACT

Apparatus for lifting a chair from without to within a bath tub, and vice versa. A person seated in the chair of the apparatus is lifted vertically upward, moved laterally into overhanging relationship with respect to the bath tub, and lowered into proximity of the bottom of the tub. After completing the bath, the person is lifted vertically upward, moved laterally away from the tub, and moved vertically downward, where the person can then be transferred to a wheel chair or the like. The chair of the bath lift apparatus is suspended in journaled relationship from a cantilever arm and a pilot arm maintains the chair orientated in a particular direction as it is moved. The apparatus includes means by which a domestic water supply can be utilized as a power source for actuating the apparatus. A cam and cam follower apparatus, together with a switch means enables the chair to be automatically guided along the before described path of travel.

United States Patent. 91

Sullivan June 11, 1974 Primary Examiner-Harvey C. Hornsby Assistant Examiner-Donald B. Massenberg Attorney, Agent, or Firm-Marcus L. Bates [5 7 ABSTRACT Apparatus for lifting a chair from without to within a bath tub, and vice versa. A person seated in the chair of the apparatus is lifted vertically upward, moved laterally into overhanging relationship with respect to the bath tub, and lowered into proximity of the bottom of the tub. After completing the bath, the person is lifted vertically upward, moved laterally away from the tub, and moved vertically downward, where the person can then be transferred to a wheel chair or the like.

The chair of the bath lift apparatus is suspended in joumaled relationship from a cantilever arm and a pilot arm maintains the chair orientated in a particular direction as it is moved.

The apparatus includes means by which a domestic water supply can be utilized as a power source for actuating the apparatus. A cam and cam follower apparatus, together with a switch means enables the chair to be automatically guided along the before described path of travel.

11 Claims, 8 Drawing Figures PA'TENTEuJun 1 1 I974 33315; 163

sum 2 or 3 FIG. 2

PATENTEDJUN 1 1 I974 3L8 15; l 68 sum 3 0r 3 FIG.

BATH LIFT APPARATUS BACKGROUND OF THE INVENTION Bath lift apparatus previously have been proposed as evidenced by US. Pats. No. 3,188,657; 3,166,282; and 2,697,475; to which reference is made for further background of the invention. In these and other prior art bath lift apparatus, inadequate provision has been made for maintaining the chair orientated in a particular direction while the chair is lifted, moved laterally, and lowered into the tub. Moreover, there is lacking in the prior art a simple mechanism which is sufficiently rugged in construction to facilitate translocation of obese persons into and out of a bath tub.

It would be desirable to have associated with the bath lift mechanism, an apparatus for precisely guiding the chair as it moves from without to within the tub, and vice versa, so that the patient, if desired, can control the action of the chair by simply turning a control valve to one of three alternate positions. Hence, the patient, if he has the capability of moving from a wheel chair into another chair, can safely tend to this aspect of his personal toilet, unassisted by others.

The present invention is particularly useful for assisting the invalid, the aged, and the obese, into and out of a bath tub in a safe and reliable manner.

SUMMARY OF THE INVENTION The present invention comprehends a chair lift for supporting a person seated therein, so that the person can be moved from without to within a bath tub, and vice versa. In the preferred form of the invention, this expedient is attained by utilizing hydraulic or hydrostatic pressure. The chair is supported by a movable vertical member, which is supported by and moves relative to a vertical stationary member. Spaced apart parallel arms have the depending ends thereof spaced apart from one another and attached to the chair, with one of the arms supporting the chair from the movable member. The arms effectively form a parallelogram so that when the chair is moved laterally of the tub, the chair remains orientated in the same direction.

A cam way and a cam follower is formed in the members. The cam follower proceeds through the cam way so as to exactly guide the chair vertically and laterally as the chair is moved from without to within the tub, and vice versa.

A primary object of this invention is the provision of a chair lift apparatus for transporting persons from without to within a bath tub, and vice versa.

Another object of the invention is to provide a chair lift device that maintains the chair orientated in the same general direction as it moves from without to within a bath tub, and vice versa.

Another object of this invention is to provide a cam way and a cam follower assembly for use in chair lift apparatus to control the direction and magnitude of movement of the chair as it proceeds from without to within a bath tub, and vice versa.

A further object of this invention is to disclose and provide a chair lift apparatus for use in combination with a bath tub'wherein spaced apart arms forming a parallelogram maintain the chair orientated in a particular direction, while a cam way and a cam follower guide the chair along a predetermined path as it moves from without to within a bath tub, and vice versa.

A still further object of this invention is to provide a chair lift apparatus which utilizes oil over water as a source of power formoving the chair from without to within a bath tub, and vice versa.

These and various other objects and advantages of the invention will become readily apparent to those skilled in the art upon reading the following detailed description and claims and by referring to the accompanying drawings. The above objects are attained in accordance with the present invention by the provision of a combination of elements which are fabricated in a manner substantially as described in the above abstract and summary.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a chair lift apparatus made in accordance with the present invention, with some parts thereof being broken away and the remaining parts being shown in cross section so as to better illustrate various teachings of this invention;

FIG. 2 is a broken, part schematical, top plan view of the apparatus disclosed in FIG. 1;

FIG. 3 is a broken, side elevational view of part of the apparatus seen in FIGS. 1 and 2;

FIG. 4 is a fragmentary, part cross-sectional view taken long line 44 of FIG. 3;

FIG. 5 is an enlarged detailed view which sets forth an important part of this invention;

FIG. 6 is a cross-sectional, part schematical representation of apparatus which can be used in conjunction with the apparatus of- FIG. 1;

- FIG. 7 is a top plan view similar in many respects to the illustration of FIG. 2, and

FIG. 8 is an enlarged, fragmentary, cross-sectional, detailed representation of part of the structure seen in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION In FIG. 1, the arrow at numeral 10 generally indicates the preferred form of a bath lift apparatus made in accordance with the present invention. As seen in FIG. 1, in conjunction with some of the remaining figures, a chair 11 is supported by the remainder of the apparatits, and is adapted to be moved by part of the apparatus from without to within the tub, and vice versa, as will be explained in more detail as the disclosure proceeds. Means are provided by which the chair can be folded back towards the remainder of the apparatus along the dashed line, if such an expedient is deemed desirable.

Cantilever arm 12 is rigidly affixed to a vertically disposed movable cylindrical member 13, so as to enable the chair to be moved vertically relative to the floor 14, and to be moved pivotally relative to the vertical longitudinal-axis of the cylinder. Wall 15 is usually located adjacent to the tub 16 so that the wall and floor can be utilized in anchoring various components of the apparatus; although it would be within the comprehension of this invention to provide other or additional supporting structure if such a requirement should be deemed necessary in order to carry out the invention.

Water inlet 17 is connected to a suitable source of water and to a water disposal outlet by means of a three-way valve, as will be pointed out in greater detail later on in this disclosure.

A cylindrical stationary vertical support member 18 is telescopingly received within the movable member in low friction engagement therewith so that one member can be moved relative to the other to thereby effect vertical as well as pivotal movement of the chair. The stationary member has an inside peripheral wall surface 19. A closure member forms the upper terminal end of the stationary member, and includes a centrally located aperture 20' therein. Numeral 21 generally indicates the inside peripheral wall surface of the movable member. It is preferred that the two vertical members be cylindrical in form and provided with seal means therebetween at a location as indicated by the numeral 21 in FIG. 8, the details of which will be more fully discussed later on.

The upper extremity of the movable member is provided with a closure means so as to form a sealed terminal end at 22 and to form a variable fluid containing chamber between the spaced apart closure members. The lowermost edge portion of the movable member is indicated by numeral 23. Flanges 24 and 25 are spaced apart from one another and rigidly affixed to the movable member, as by welding or the like, and cooperate together and with the movable member to form an outwardly directed circumferentially extending toroid or groove. Bearing member 26 is slidably received on a polished rod 27 and is captured within the toroid so that the bearing member is forced to move with the movable member as the chair is moved about within its limits of rotation.

The polish rod has the opposed depending ends 28 and 29 thereof, respectively, attached to anchor points 30 and 31, respectively. While the anchor member'30 and plate member 31 are illustrated as being affixed to wall structure and floor structure, respectively, it should be realized that the apparatus could be mounted to a horizontal base framework having a vertical end member, to each of which the anchor members could suitably be affixed so as to impart the apparatus with portability.

The cantilever arm 32 has one end portion thereof rigidly affixed to the movable member by means of welding as illustrated at 33. The opposed end portion of the cantilever arm is welded at 34 to a vertical tubular housing 35. The housing receives a vertically disposed shaft 36 therethrough so that the shaft can be r0- tated relative to the housing 35. The upper extremity of the shaft is provided with an enlargement 37 in the form of a thrust bearing which bears against the upper extremity of housing 35. Web 38 is welded to shaft 36 so as to provide a means by which the load presented by the chair and its occupant can be safely transferred into the vertical shaft 36, into the housing 35, along the cantilever arm 32, into the movable member, into the stationary member, and finally into the base plate or floor structure.

Plate 39 is rigidly-affixed to shaft 36 and is provided with a vertically disposed aperture for removably receiving pin 40 therethrough. Pin 40 is affixed to one terminal end of a pilot arm 41. The pilot arm includes an opposed terminal end which is affixed to the before mentioned follower bearing 26. The pilot arm can be detached from the chair by removing the pin from the plate, thereby enabling 360 of rotation of the chair about the vertical axis of the shaft 36.

Cut-out 42 is formed within each of the spaced apart flanges so as to enable portions of a switch assembly associated with a cam follower to pass therethrough, for

purposes which will be better appreciated later on in the disclosure.

In FIGS. 2 and 7, the dot-dashed lines illustrate one position which the cantilever and pilot arms assume when the chair is moved to an alternate position as it is placed from without to within a bath tub.

Looking now to the details of FIGS. 3-5, there is seen a cam way 43 which is formed within the movable member. The cam way commences at 44 and vertically follows a downward path as it curves toward apex 46, then reverses its path to depend vertically upwards towards its terminal end 45. Accordingly, the cam way includes two spaced apart parallel legs which are in communication in that they curve together towards the lowermost position seen illustrated by the numeral 46.

- may be provided with a close tolerance fit by suitably affixing the follower and the switch means to the cylinders by using fasteners other than as desclosed herein.

A cam follower 50 includes a threaded fastener 51 which is received through a drilled passageway 52, and has a low friction roller means 53 joumaled thereto, so as to enable the roller to be received within the cam way in close tolerance relationship therewith. In FIG. 5 numerals 54, 55, and 56 illustrate various ones of an infinite number of positions which the cam follower can assume as it proceeds from one leg, through the apex, and towards the other leg of the cam way.

Numeral 57 indicates the outermost edge portion of the cam way, while numeral 58 indicates the innermost edge portion of the cam way. The roller 53 of the cam follower can bear against either side, as may be required.

The switch means includes a journal means 59 which has a portion thereof made in the form of a threaded fastener. The fastener extends through a drilled passageway 60 radially formed within the movable member so as to pivotally or rotatably receive an over the center member 61 thereon. Member 61 has a limited concave upper surface 62 adjacent to opposed crescent 0r convex shaped edge portions 63 and 64, each of which are joined together at 65.

Extension shaft 66 is affixed to member 62 and supports counter-weight 67 at the free depending end thereof.'

Spaced apart stop means 68, 68' limit the amount of pendulum-like travel of the over-the-center member. Numeral 69 indicates the second or alternate position of the over the center switch member.

Looking again to the details of the movable and fixed cylindrical support members, numeral 70 indicates a resilient seal means which precludes flow of fluid which might otherwise escape from the upper fluid containing chamber through the annulus 72. An annular teflon member 71 is affixed to the stationary member and; provides a low friction bearing means so as to enable low friction engagement between the component parts of the apparatus as the movable member telescopingly and rotatably moves relative to the fixed member. A second Teflon member is affixed to the stationary member in spaced apart relationship to the member 71 so as to provide spaced apart bearing means for maintaining the fixed and movable members axially aligned relative to one another.

FlG. 6 illustrates one form of the before mentioned three-way valve which can be used in conjunction with the present invention. As seen in FIG. 6, numeral 700 broadly illustrates a conventional three-way valve. The apparatus includes a movable valve element 710 enclosed within housing 720, and having an inlet and an outlet 750, fluid pressure inlet 173, and spent power fluid outlet 740. Outlet 740 is connected to the sewer system; conduit 173 to a domestic source of water pressure, and conduit 750 to the before mentioned conduit 17. The dashed line illustrates the position of the valve when water is flowing into the chair lift apparatus. It is preferred to fill the upper portion of the chamber with oil, to thereby provide an oil over water system which reduces the corrosion to which the system is otherwise subjected.

In operation, the chair is positioned in the illustrated I solid line position of FIGS. 1, 2, or 7. The three-way valve has been positioned so that the chair is at the lowermost position of travel, and located without the tub. The cam follower 50 accordingly is positioned at the upper extremity 44' of the cam way. The chair is folded into the usable position and the patient seated-therein, after which the three-way valve is turned to the position which admits water into conduit 17. The valve can be located in proximity to the patient so that he can manipulate the chair, if desired.

As water flows into the stationary member, fluid pressure is effected through orifice thereby subjecting the chamber above plate 20 to increase pressure, whereupon the movable member is forced in an upward direction since the liquid cannot flow pastthe seal means 70. As the movable member carries the chair in an upward direction, the cam follower bears against side 57 of the cam way, eventually urging the chair to commence to move laterally respective of the bath tub.

The cam follower at 56 continues to move to its lowermost position 46 whereupon vertical motion is arrested. The over the center member is located at 61' during this step of the operation. The valve means is then moved to its second position, allowing water to drain from the inlet as the upper chamber is emptied of liquid.

As water drains from the upper chamber, the movable member vertically descends, causing the cam follower to ultimately engage the side 63 of the over the center member. The cam follower bears against surface 63 and accordingly is forced to move upward and outward following the configuration of the convex edge portion, until the cam follower is guided into leg 45 of the cam way, where the cam follower rotates the movable member as the cam way continues to be guided by the cam follower until the follower engages the terminal end 45 of the second leg. The over the center member is rotated into position 67 as the follower moves against surface 63 thereof. The chair is now positioned at the lower extremity of the bath tub and the patient can bathe himself in any desirable manner.

When the patient is ready to transport himself out of the tube he again moves the three-way valve means to the position which enables hydrostatic pressure to again lift the movable member until the cam follower is again positioned at location 55. At this position, the over the center member is positioned at the full line position 67, so that when the three-way valve is moved to the exhaust position, the follower will engage face 64 of the over the center member, causing the follower to move into leg 44 of the cam way, while at the same time resetting the over the center member into position 69.

The movable member continues to move vertically downward until the follower abuts the terminal end 44 of the cam way, thereby positioning the chair without the tub as illustrated at 11' in FIG. 2 or 7.

Where space is at a premium, the chair can be attached to the plate 39 in the illustrated manner of H0. 7 so as to enable arms 32 and 41 to be shortened. In both FIGS. 2 and 7 the bath tub is located in underlying relationship respective to the dashed line portion of the illustration ll, of course. It is preferred to maintain the volume of chamber 19 at a value which is greater than the displacement of the upper chamber so that a sufiicient quantity of oil can always be present above the water in the lower chamber to preclude entrance of water into the upper chamber. Hence water flows into and out of the fixed or lower chamber while oil flows into and out of the variable or upper chamber, with the interface of the air-over-oil system remaining within the lower chamber.

1 claim:

1. A bath lift apparatus for assisting a person in out of a bath tub, comprising:

a stationary vertical support member, a movable vertical support member; means by which said stationary and movable vertical support members are telescopingly received one within the other to form a coacting piston and a cylinder arrangement, means by which one of the members can be caused to controllably move within the other so as to effect reciprocatory and axial relative motion thercbetween;

a cantilever arm having an end affixed to and another end extending outwardly from said movable member, a chair means, journal means by which said chair means is supported in joumaledrelationship respective to the extending end of said cantilever arm for rotation about a fixed vertical axis spaced from and parallel to the longitudinal central axis of said vertical support members; a pilot arm having opposed end portions, means by which one said end portion of said pilot arm is journaled about said fixed vertical axis in spaced relationship to said movable member with one remaining end portion and of said pilot arm being jou'rnaled to said chair means in spaced relation to said extending end of said cantilever arm; said pilot arm and said cantilever arm being horizontally spaced from one another to effectively describe a parallelogram so that relative rotation between said members imparts pivotal movement to said pilot arm thereby causing said chair means to pivot about its journal means while the chair means remains orientated in the same relative direction as said chair means is elevated from a position externally of the tub, moved laterally into overlying relationship relative to the tub, and lowered towards the bottom of the tub, and means connected between said stationary and said movable support members for imparting relative rotational motion between said stationary and said movable support members as said stationary and said movable support members are moved in a telescopic manner with respect to one another.

2. The apparatus of claim 1 wherein said pilot arm includes journal means by which said remaining end portion is removably affixed to said chair means so as to enable said remaining end portion of the arm to be removed from the chair means and the chair means rotated about said means by which said chair means is journaled. v

3. The apparatus of claim 1, and further including a cam way in one of said members, a cam follower in the other of said members;

said cam way having a configuration which, when said cam follower traverses the length thereof, causes the chair to be moved laterally as the chair is lifted vertically, and then lowered into a tub.

4. The apparatus of claim 3, and further including a switch means; said cam way being in the form of two leg portions having upper and lower terminal ends which are spaced from one another at one upper marginal terminal end thereof and joined together at the other lower terminal end;

said switch means being disposed at the joined together portion of said two leg portion for causing said cam follower to travel from one leg to the other as said movable member moves the chain means from without to within the tub, and vice versa.

5. The chair lift apparatus of claim 4 wherein said switch means is an over-the-center member having means by which it is journaled to the member within which the cam way is formed so that the switch means, when it is reset, is moved from a first to an alternate position, and vice versa;

said reset means being opposed surfaces formed on said over-the-center member; one of said opposed surfaces being positioned to move said follower into one of said legs and the other of said opposed surfaces being positioned to move said follower into the other of said legs; said opposed surfaces being arranged so that when one said opposed surface is engaged by said cam follower, said over-thecenter member is moved from one to the other of said first and alternate positions.

6. A bath lift apparatus for assisting a person in and out of a bath tub, comprising:

a stationary vertical support member, a movable vertical support member; means by which said stationary and movable vertical support members are telescopingly received one within the other to form a coacting piston and a cylinder arrangement, means by which one of the members can be caused tocontrollably move within the other so as to effect reciprocatory and pivotal relative motion therebetween;

a cantilever arm having an end affixed to and another end extending outwardly from said movable member, a chair means, means by which said chair is journaled to the extending end of said cantilever arm for rotation about a fixed vertical axis spaced from and parallel to the longitudinal central axis of said vertical support members; a pilot arm having opposed end portions, means by which one said end portion is journaled about said fixed vertical axis in spaced relationship to said movable member with the remaining end portion being journaled to said chair means; said pilot and said cantilever arm being horizontally spaced from one another;

cam means connected to said stationary and movable vertical support members for causing relative axial rotation between said stationary and movable vertical support members as the vertical support members are telescopingly moved relative to one another, thereby causing the chair to move laterally as the chair is elevated and lowered by said movable member.

7. Chair lift apparatus for transporting a person into and out of a bathtub, which includes a chair for supporting a person seated therein, a movable member, a fixed member, arm means by which said chair is supported from said movable member in spaced relationship therewith; I

means by which said movable member is supported by said fixed member and by which said movable member can be moved in a vertical and a pivotal direction relative to said fixed member;

cam means in'said movable and fixed members which includes a cam way formed on one of the two recited members and a cam follower formed on the other of said two members; said cam follower being captured within said cam way; said cam way includes two spaced legs joined at one end thereof and having a length which is traveled by said cam follower as the chair is moved from without to within the tub, and vice versa; a switch means including a reset means;

said switch means being located adjacent the joined portion of the cam way legs so that the cam follower is forced to engage the resetmeans as it moves from one leg to the other; and, said cam follower is forced to travel from one to the other leg as it passes the joined portion of the legs within the cam way so that when the chair is lifted by said movable member, the cam means guides the chair from within to without a bathtub, and vice versa.

8. The apparatus of claim 7 wherein said movable and fixed members are concentrically arranged cylinders which are telescopingly forced towards and away from one another by water pressure.

9. The apparatus of claim 7, and further including means forming a journal by which said chair is attached to said arm means so that said chair can be pivoted about said journal;

a pilot arm having opposed ends, one opposed end being affixed to said chair at a location spaced horizontally from the last said journal, the other opposed end of said pilot arm terminating in journaled relationship at a location spaced from said movable member; and means by which the last said journal is located in fixed position relative to said fixed member.

10. The apparatus of claim 9 wherein said arm means and said pilot arm are parallel to one another and cooperate together to form a parallelogram.

11. The chair lift apparatus of claim 7 wherein said switch means is an over-the-center member having means by which it is journaled to the member within which the cam way is formed so that the switch means, when it is reset, is moved from a first to an alternate position, and vice versa;

said reset means being opposed surfaces formed on said over-the-center member; one of said opposed surfaces being positioned to move said follower face is engaged by said cam follower, said over-thecenter member is moved from one to the other of said first and alternate positions.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Dated June 11, 197

Patent No. 3 8l5.l63

Inventor(s) Lawrence J. Sullivan It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 7, a

line 27, substitute "chair" for chain Claim 1 Column 7 lines 29 and 30, substitute -and-- for "inc Claim I Signed and sealed this 29th day of October 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents USCOMM-DC 60376-1 69 u.s. GOVERNMENT PRINTING OFFICE: is" 0-366-334,

FORM PO-105O (10-69) 

1. A bath lift apparatus for assisting a person in and out of a bath tub, comprising: a stationary vertical support member, a movable vertical support member; means by which said stationary and movable vertical support members are telescopingly received one within the other to form a coacting piston and a cylinder arrangement, means by which one of the members can be caused to controllably move within the other so as to effect reciprocatory and axial relative motion therebetween; a cantilever aRm having an end affixed to and another end extending outwardly from said movable member, a chair means, journal means by which said chair means is supported in journaled relationship respective to the extending end of said cantilever arm for rotation about a fixed vertical axis spaced from and parallel to the longitudinal central axis of said vertical support members; a pilot arm having opposed end portions, means by which one said end portion of said pilot arm is journaled about said fixed vertical axis in spaced relationship to said movable member with one remaining end portion of said pilot arm being journaled to said chair means in spaced relation to said extending end of said cantilever arm; said pilot arm and said cantilever arm being horizontally spaced from one another to effectively describe a parallelogram so that relative rotation between said members imparts pivotal movement to said pilot arm thereby causing said chair means to pivot about its journal means while the chair means remains orientated in the same relative direction as said chair means is elevated from a position externally of the tub, moved laterally into overlying relationship relative to the tub, and lowered towards the bottom of the tub, and means connected between said stationary and said movable support members for imparting relative rotational motion between said stationary and said movable support members as said stationary and said movable support members are moved in a telescopic manner with respect to one another.
 2. The apparatus of claim 1 wherein said pilot arm includes journal means by which said remaining end portion is removably affixed to said chair means so as to enable said remaining end portion of the arm to be removed from the chair means and the chair means rotated about said means by which said chair means is journaled.
 3. The apparatus of claim 1, and further including a cam way in one of said members, a cam follower in the other of said members; said cam way having a configuration which, when said cam follower traverses the length thereof, causes the chair to be moved laterally as the chair is lifted vertically, and then lowered into a tub.
 4. The apparatus of claim 3, and further including a switch means; said cam way being in the form of two leg portions having upper and lower terminal ends which are spaced from one another at one upper marginal terminal end thereof and joined together at the other lower terminal end; said switch means being disposed at the joined together portion of said two leg portion for causing said cam follower to travel from one leg to the other as said movable member moves the chain means from without to within the tub, and vice versa.
 5. The chair lift apparatus of claim 4 wherein said switch means is an over-the-center member having means by which it is journaled to the member within which the cam way is formed so that the switch means, when it is reset, is moved from a first to an alternate position, and vice versa; said reset means being opposed surfaces formed on said over-the-center member; one of said opposed surfaces being positioned to move said follower into one of said legs and the other of said opposed surfaces being positioned to move said follower into the other of said legs; said opposed surfaces being arranged so that when one said opposed surface is engaged by said cam follower, said over-the-center member is moved from one to the other of said first and alternate positions.
 6. A bath lift apparatus for assisting a person in and out of a bath tub, comprising: a stationary vertical support member, a movable vertical support member; means by which said stationary and movable vertical support members are telescopingly received one within the other to form a coacting piston and a cylinder arrangement, means by which one of the members can be caused to controllably move within the other so as to effect reciprocatory and pivotal relative motion therebetween; a cantilever arm having an end affixed to And another end extending outwardly from said movable member, a chair means, means by which said chair is journaled to the extending end of said cantilever arm for rotation about a fixed vertical axis spaced from and parallel to the longitudinal central axis of said vertical support members; a pilot arm having opposed end portions, means by which one said end portion is journaled about said fixed vertical axis in spaced relationship to said movable member with the remaining end portion being journaled to said chair means; said pilot and said cantilever arm being horizontally spaced from one another; cam means connected to said stationary and movable vertical support members for causing relative axial rotation between said stationary and movable vertical support members as the vertical support members are telescopingly moved relative to one another, thereby causing the chair to move laterally as the chair is elevated and lowered by said movable member.
 7. Chair lift apparatus for transporting a person into and out of a bathtub, which includes a chair for supporting a person seated therein, a movable member, a fixed member, arm means by which said chair is supported from said movable member in spaced relationship therewith; means by which said movable member is supported by said fixed member and by which said movable member can be moved in a vertical and a pivotal direction relative to said fixed member; cam means in said movable and fixed members which includes a cam way formed on one of the two recited members and a cam follower formed on the other of said two members; said cam follower being captured within said cam way; said cam way includes two spaced legs joined at one end thereof and having a length which is traveled by said cam follower as the chair is moved from without to within the tub, and vice versa; a switch means including a reset means; said switch means being located adjacent the joined portion of the cam way legs so that the cam follower is forced to engage the reset means as it moves from one leg to the other; and, said cam follower is forced to travel from one to the other leg as it passes the joined portion of the legs within the cam way so that when the chair is lifted by said movable member, the cam means guides the chair from within to without a bathtub, and vice versa.
 8. The apparatus of claim 7 wherein said movable and fixed members are concentrically arranged cylinders which are telescopingly forced towards and away from one another by water pressure.
 9. The apparatus of claim 7, and further including means forming a journal by which said chair is attached to said arm means so that said chair can be pivoted about said journal; a pilot arm having opposed ends, one opposed end being affixed to said chair at a location spaced horizontally from the last said journal, the other opposed end of said pilot arm terminating in journaled relationship at a location spaced from said movable member; and means by which the last said journal is located in fixed position relative to said fixed member.
 10. The apparatus of claim 9 wherein said arm means and said pilot arm are parallel to one another and cooperate together to form a parallelogram.
 11. The chair lift apparatus of claim 7 wherein said switch means is an over-the-center member having means by which it is journaled to the member within which the cam way is formed so that the switch means, when it is reset, is moved from a first to an alternate position, and vice versa; said reset means being opposed surfaces formed on said over-the-center member; one of said opposed surfaces being positioned to move said follower into one of said legs and the other of said opposed surfaces being positioned to move said follower into the other of said legs; said opposed surfaces being arranged so that when one said opposed surface is engaged by said cam follower, said over-the-center member is moved from one to the other of said first and alternate positions. 